Sonic difference between the CAT JL2 Sig & CAT JL3

I am looking for direct comparisons of these two amps, preferably, in the same system. I spoke with Ken Stevens at length today and he was adamant about the ability of his amps to significantly (his words were "STOMP") outperform anything out there. I would like to know in what areas the JL3 outperforms the JL2 Sig. Is it in all areas, or more significantly in particular areas. I think Ken mentioned bass extension for example. It would have to be a MAJOR step up to justify the cost differential and HEAT differential. The rest of the system is CAT Ultimate MK2 pre, Audiologic 24MXL DAC, CEC TL2 transport, Manley 350 amps (the weakest link) amd Avalon Osiris speakers. Everything is wire with Stealth top of the line cables. My room is 31' X 19.5' with a ceiling that starts at 8' and slopes to 13' symetrically. Any relevant input is appreciated. I hope the thread stays on point though and doesn't turn into a pissing contest. Thanks. Bart